Crafty Crows Can Build Tools From Memory

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iStock

Scientists have discovered yet another reason to never get on a crow's bad side. According to new research reported by Gizmodo, members of at least one crow species can build tools from memory, rather than just copying the behavior of other crows—adding to the long list of impressive skills that set these corvids apart.

For the new study, published in the journal Scientific Reports, an international team of scientists looked at New Caledonian crows, a species known for its tool usage. New Caledonian crows use sticks to pick grubs out of logs, sometimes stashing these twigs away for later. Tools are so important to their lifestyle that their beaks even evolved to hold them. But how exactly the crows know to use tools—that is, whether the behavior is just an imitation or knowledge passed down through generations—has remained unclear until now.

The researchers set up the experiment by teaching eight crows to drop pieces of paper into a box in exchange for food. The birds eventually learned that they would only be rewarded if they dispensed either large sheets of paper measuring 40-millimeters-by-60 millimeters or smaller sheets that were 15-millimeters-by-25 millimeters. After the crows had adapted and started using sheets of either size, all the paper was taken away from them and replaced with one sheet that was too big for the box.

The crows knew exactly what to do: They ripped up the sheet until it matched one of the two sizes they had used to earn their food before and inserted it into the dispenser. They were able to do this with out looking at the sheets they had used previously, which suggests they had access to a visual memory of the tools. This supports the "mental template matching" theory—a belief among some crow experts that New Caledonian crows can form a mental image of a tool just by watching another crow use it and later recreate the tool on their own, thus passing along the template to other birds including their own offspring.

This is the first time mental template matching has been observed in birds, but anyone familiar with crow intelligence shouldn't be surprised: They've also been known to read traffic lights, recognize faces, nurse grudges, and hold funerals for their dead.

[h/t Gizmodo]

Pet Obesity is Causing Big Health Problems, According to a New Report

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iStock/dennisvdw

If you’ve recently picked up your cat and felt your back give out, your furry friend may be among the 60 percent of the feline population that’s overweight. Dogs are also getting chubbier: about 56 percent of pet pooches are obese.

According to Banfield Pet Hospital, America's largest general veterinary practice with more than 1000 hospitals nationwide, those fat cats and chunky puppies are at risk for chronic health issues. In a new report, the hospital finds that osteoarthritis (OA) in pets is on the rise, with a 66 percent increase in dogs and a 150 percent increase in cats over the past 10 years.

Osteoarthritis is a kind of arthritis caused by inflammation or damage in joint tissue. Genetics, injury, or bone abnormalities can all be factors. The disease is chronic and degenerative and can make it difficult for pets to move around as they get older.

Excess weight can both precede OA and make it worse. When a pet is overweight, they can develop chronic pain that leads to stress on joints. If they already have OA, that joint discomfort can prevent them from being active, leading to weight gain. That worsens the condition, and the cycle continues.

A dog is 2.3 times more likely to be diagnosed with OA if it's obese, while cats are 1.2 times more likely. Dogs suffering from the condition tend to display symptoms like putting their weight off to one side when sitting, avoiding stairs, or appearing uninterested in playing. Cats might have loose or matted hair because they can't maneuver to groom certain parts of their body.

Although OA can be seen at any age, it’s often mistaken for old age and a pet slowing down naturally. If you notice your pet is either soft around the middle or moving more slowly, it’s best to see a veterinarian. Pets who are overweight or suffering from OA—or both—can benefit from treatments like special diets.

There Are 2373 Squirrels in New York's Central Park, Census Finds

iStock/maximkabb
iStock/maximkabb

Central Park in New York City is home to starlings, raccoons, and exotic zoo animals, but perhaps the most visible fauna in the area are the eastern gray squirrels. Thanks to a team of citizen scientists, we now know exactly how many of the rodents occupy the space—approximately 2373 of them, according to a census reported by Smithsonian.

In October 2018, a group called the Squirrel Census—with help from the Explorers Club, the NYU Department of Environmental Studies, Macaulay Honors College, the Central Park Conservancy, and the New York City Department of Parks & Recreation—organized a squirrel survey across all 840 acres of Central Park. For 11 days, more than 300 volunteers staked out their sections of the park twice a day—at dawn and dusk when the crepuscular animals are most active—and noted each squirrel they spotted. They also recorded how the squirrels looked, vocalized, behaved, and reacted to humans.

The research was analyzed and presented at an Explorers Club event in New York City on June 20. All the non-peer-reviewed findings—which includes a printed report, an audio report on a vinyl 45, 37 pages of data, collectible squirrel cards, and large maps of the park and the squirrel locations—are available to purchase for $75 from the Squirrel Census website.

This isn't the first time a massive census has been conducted of a public park's squirrel population. In 2011, the Squirrel Census launched with its first survey of Atlanta's Inman Park. They've conducted satellite squirrel counts at other parks, but Central Park is just the second park the organization has investigated in person.

[h/t Smithsonian]

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